Queen promotions 3

a) 1.Se5 Qb8 2.Kd6 exd8Q#

b) 1.Ke6 e8Q+ 2.Se7 Qa2#

Of course, white needs really many linemovers to allow the mates with quadruple pins. That's why he promotes. Rook promotion is not enough as it is necessary not only to pin or check on vertical line, but there is also a need of guard on diagonal.

a) 1.g5 Sh6 2.Ke5 a8Q 3.Kf6 Qh8#

b) 1.Rg8 Se5 2.Rb8 axb8Q 3.Kc3 Qb2#

Two simple model mates by promoted queens.

a) 1.e1R g7 2.e2 g8Q 3.Ke3 Qg3#

b) 1.c1R f7 2.c2 f8Q 3.Kc3 Qa3#

Two echo model mates by promoted queen, sequences include also black rook promotions as it is the only unit not guarding mating line.

1.Bxc7 b8Q 2.Ba5 Rg7 3.Qe2 Qg3#

1.Bxb7 c8Q 2.Ba6 Rh7 3.Kg3 Qh3#

Chameleon echo play in two solutions. Black first clears line of wR and unpins it by bishop that is not blocking in given mate. White in the meantime promotes queen and then, after supporting move by wR, he mates far on the king's flank. By the way - Zilahi.

1...c7 2.Kf4 Kf6 3.Kg4 c8Q+ 4.Kh5 Qh3#

1...Kf7 2.Kd6 c7 3.Kd7 Kf6 4.Ke8 c8Q#

Again echo mates by promoted queen, this time with 3 units only.

1...Bxc7 2.Kxc7 Kg1 3.Kb8 d8Q#

1.Bxb8 Kg1 2.Ba7 Kf2 3.Bb8 Kf3 4.Ba7 Ke4 5.Bb8 Kxd4 6.Ba7 Ke3 7.Bb8 d4 8.Ba7 d5 9.Bb8 d6 10.cxd6 a7 11.d5 axb8Q#

In set play White mates quickly, by promoting to queen at d8. In solution, however, Black is forced to kill wB and thus it takes much more time to allow (other) wP to promote.

1.Kd7 Kg1 2.Kc6 Kh1 3.Kb5 Kg1 4.Ka4 Kh1 5.Ka3 Kg1 6.Kb2 Kh1 7.Kxc2 Kg1 8.Kxc3 Kh1 9.Kd4 Kg1 10.c3 Kh1 11.c2 Kg1 12.c1Q Kh1 13.Qe1 Kg1 14.Qf2+ Kh1 15.Qf5 exf5 16.Ke4 f6 17.Kf5 f7 18.Kf6 f8Q#

Well, it is classical long helpmate. WK only oscillates, while his black colleague eats out the way for bP, that promotes and allows white promotion. It is a pity it couldn't be constructed such that bK started at f6, it would be really astonishing round trip...